Fluorescent red and magenta waterfast ink jet inks

Abstract

Aqueous fluorescent inks are disclosed that fulfill United Sites Postal Service requirements for franking and/or automation compatibility, while being able to be used in an ink jet printer. The inks of this invention may be read by current United States Postal Service equipment. The inks are red fluorescent and waterfast, having improved print quality. The formulations are based on water, cosolvent and penetrant solutions of fluorescent toners. The cosolvents are low vapor pressure, polar solvents, and glycol ethers as penetrants.

What is claimed is: 
     
       1. A postage metering system having a printing mechanism for printing postage, the improvement comprising: within the printing mechanism employing a red aqueous magenta waterfast fluorescent ink containing water, water soluble organic solvents, red fluorescent soluble toners and glycol ether as a cosolvent penetrant that are inert to the materials contained in the printing mechanism. 
     
     
       2. The system of claim 1, wherein the red aqueous waterfast fluorescent ink composition consists essentially of: a. 35-55 (Wt. %) water;   b. 15-50 (Wt. %) water soluble organic solvents having a hydrogen bonding solubility parameter (δ h ) greater than 8.0, a polar solubility parameter (δ p ) greater than 5.0 and a dispersion parameter (δ.sub.δ) between 7-8.3;   c. 5-15 (Wt. %) red fluorescent soluble toners with a average molecular weight between 200 and a 1,000; and   d. 5-15 (Wt. %) of glycol ether as a cosolvent penetrant.   
     
     
       3. The system of claim 1, wherein the red waterfast aqueous fluorescent ink composition consists essentially of: a. 35-55 (Wt. %) water;   b. 15-50 (Wt. %) water soluble organic solvents having a hydrogen bonding solubility parameter (δ h ) greater than 5.0, a polar solubility parameter (δ p ) between 8.0-8.7 and a dispersion parameter (δ.sub.δ) between 8.4-10.0;   c. 5-15 (Wt. %) fluorescent soluble toners with a molecular weight between 200 and a 1,000; and   d. 5-15 (Wt. %) of glycol ether as a cosolvent penetrant.   
     
     
       4. The system claimed in claim 1, wherein said printing mechanism is an ink jet printer. 
     
     
       5. A red aqueous waterfast fluorescent ink composition consisting essentially of: a. 35-55 (Wt. %) water;   b. 15-50 (Wt. %) water soluble organic cosolvents having a hydrogen bonding solubility parameter (δ h ) greater than 8.0, a polar solubility parameter (δ p ) greater than 5.0 and a dispersion parameter (δ.sub.δ) between 7-8.3;   c. 5-15 (Wt. %) red fluorescent soluble toners with a average molecular weight between 200 and a 1,000; and   d. 5-15 (Wt. %) of glycol ether as a cosolvent penetrant.   
     
     
       6. The composition of claim 5, wherein the cosolvent penetrant is a glycol ether. 
     
     
       7. The composition of claim 6, wherein the glycol ether is selected from the group consisting of triethylene glycol ethyl ether, diethylene glycol ethyl ether, diethylene glycol propyl ether; tetraethylene glycol dimethyl ether, tripropylene glycol ether, tripropylene glycol isopropyl ether, propylene glycol butyl ether, diethylene glycol monohexyl ether or diethylene glycol butyl ether. 
     
     
       8. The composition of claim 7 wherein the glycol ethers have a viscosity of less than 20 cps. 
     
     
       9. The composition of claim 5, wherein the fluorescent toner is selected from the group consisting of urea formaldehyde toluene sulfonamide, polyester polyamide or dim ethyl hydantoin formaldehyde. 
     
     
       10. The composition of claim 9, wherein the polyester polyamide fluorescent toner has an acid number greater than 50. 
     
     
       11. The composition of claim 5, wherein the water soluble organic solvents individually or in solution do not exceed a viscosity of 20 cps. 
     
     
       12. The composition of claim 5, wherein the water soluble organic solvents have a vapor pressure less than 1 mm/Hg at room temperature. 
     
     
       13. The composition of claim 12, wherein the water soluble organic solvents is a glycol. 
     
     
       14. The composition of claim 5, further including 0.1 to 3.0 (Wt %) toning dye belong to the categories of acid, direct or basic dyes in order to increase the optical density without decreasing the fluorescence. 
     
     
       15. The composition of claim 14, wherein the toning dye is selected from the group consisting of C.I. Direct Yellow 86, C.I. Acid Yellow 210, C.I. Basic Yellow, 40, C.I. Basic Yellow 51, C.I. Basic Yellow 2. 
     
     
       16. The composition of claim 15, wherein the toning dye is soluble in the organic solvent and the penetrant. 
     
     
       17. The composition claimed in claim 5, wherein the soluble toners contain non ionic surfactants to increase the solubility of the ink. 
     
     
       18. The composition claimed in claim 17, wherein the non ionic surfactant has an HLB between 8 and 15. 
     
     
       19. The composition claimed in claim 18, wherein the non ionic surfactant is selected from the group consisting of: tridecyl alcohol alkoxylates and nonyl phenoxy poly (ethyleneoxy) ethanol. 
     
     
       20. The composition claimed in claim 19, wherein the non ionic surfactant is used at concentrations from trace to 3 Wt. %. 
     
     
       21. A red aqueous waterfast fluorescent ink composition consisting essentially of: a. 35-55 (Wt. %) water;   b. 15-50 (Wt. %) water soluble organic solvents having a hydrogen bonding solubility parameter (δ h ) greater than 5.0, a polar solubility parameter (δ p ) between 8.0-8.7 and a dispersion parameter (δ.sub.δ)between 8.4-10.0;   c. 5-15 (Wt. %) fluorescent soluble toners with a molecular weight between 200 and a 1,000; and   d. 5-15 (Wt. %) of glycol ether as a cosolvent penetrant.   
     
     
       22. The composition of claim 21, wherein the fluorescent toner is selected from the group consisting of urea formaldehyde toluene sulfonamide, polyester polyamide or dimethyl hydantoin formaldehyde. 
     
     
       23. The composition of claim 21, wherein the water soluble organic solvents are selected from the group consisting of 2-pyrrolidone, N-methyl pyrrolidone, sulfolane, or gamma butyrlactonelactone. 
     
     
       24. The composition of claim 21, further including 0.1 to 3.0 (Wt %) toning dye belonging to the categories of acid, direct or basic dyes. 
     
     
       25. The composition of claim 24, wherein the toning dye is selected from the group consisting of C.I. Direct Yellow 86, C.I. Acid Yellow 210, C.I. Basic Yellow, 40, C.I. Basic Yellow 51, C.I. Basic Yellow 2. 
     
     
       26. The composition of claim 24, wherein the toning dye is soluble in the organic solvent and the penetrant.